Question: Simplify the following expression: $a = \dfrac{n}{9} + \dfrac{n}{6}$
Explanation: In order to add expressions, they must have a common denominator. The smallest common denominator is the least common multiple of $9$ and $6$ $\lcm(9, 6) = 18$ $ a = \dfrac{2}{2} \cdot \dfrac{n}{9} + \dfrac{3}{3} \cdot \dfrac{n}{6} $ $a = \dfrac{2n}{18} + \dfrac{3n}{18}$ $a = \dfrac{2n +3n}{18}$ $a = \dfrac{5n}{18}$